A triangle has corners at (6 ,5 )(6,5), (1 ,-6 )(1,6), and (-2 ,9 )(2,9). If the triangle is dilated by a factor of 5 5 about point #(5 ,-5 ), how far will its centroid move?

1 Answer
Feb 10, 2018

Centroid moves by ~~ color(green)(33.44)33.44 due to dilation factor of 5 about point ((5),(-5))

Explanation:

Centroid G( ((6+1-2)/3),((5-6+9)/3)) = ((5/3),(8/3))

Dilated about ((5),(-5)) by a factor of 5

New coordinates of centroid G'

vec(G'D( = 5 * vec(GD)

((x-5),(y+5)) -> 5((5/3 - 5),(8/3+5)) = ((50/3),(115/3))#

G'((x),(y)) = ((15),(100/3))

Distance between G & G'

vec(GG') = sqrt((15-5/3)^2 + (100/3-8/3)^2) ~~ color(green)(33.44)